Short-circuiting device



Oct. 13, 1925. 1,557,080

H. D. MuRnocK SHCRT CIRCUITING DEVICE 5 Filerlay 19. 1922 WITNESSES:INVENTOR @f He my l). /Wurdoc/f Patented Cet. 13, 1925.

UNITED STATES HENRY D. MURDOCK, OF WILKINSBURG, HOUSE ELECTRIC &MANUFACTURING VAN'IA.

PENNSYLVANIA, .ASSIGNOR TO WESTING- COMPANY, A CORPORATION OF PENNSYL-SHORT-CIRCUITING DEVICE.

Application filed May 19,

To all 'whom t may concern.:

Be it known that I, HENRY D. Mnnnoox, a citizen of the United States,and a resident of IVilkinsburg, in the county of Allegheny and State ofPennsylvania, have invented a new and useful Improvement inShort-Circuiting Devices, of which the following is a specification. l

My invention relates to short-circuitmg devices and it has particular'relation to centrifugally operated mechanism for employment withdynamo-electric machines to effect a repulsion operation during. thestarting period and an induction operation during the normal operatingperiod of the machine.

One of the objects of the invention is to provide a centrifugallyactuated short-circuiting device that is simple in construction andinexpensive to manufacture.

Another object of the invention is to provide a device of the characterdescribed in l which the contact members may be easily adjustedrelatively to the commutator seg ments.

A further object of the invention is to provide a device of the classset forth embodying comparatively few parts which may be quickly andeasily assembled.

In the accompanying drawing:

Fig. 1 is a transverse sectional view of a portion of a dynamo-electricmachine, taken on the line I-I of Fig. 2.

Fig. 2 is a longitudinal sectional view taken on the line II-II of Fig.1.

Referring to the drawing, a portion of a dynamo-electric machine isconventionally illustrated as comprising a shaft 1 upon which a rotormember 2 provided with a commutator cylinder 3 is mounted for co- 40operation with a stator member, not shown.

The rotor member 2 is provided, at one end, with a plurality ofoutwardly extending studs 4 to which a short-circuiting ring 5 issecured by means of screws G. The ring 45 5 may be spaced from the shaft1 and is electrically insulated from the screws 6 by means of flangedsleeve members 7, of fibrous material, and from the studs 4 by means ofinsulating washers 8.

A plurality of spring contact members, indicated, as a whole, by thenumeral 9, are secured to the inner face of the ring 5, adja cent to theperiphery thereof, and extend to a point adjacent to the extremities ofthe 55 segments of the commutator cylinder 3.

1922. Serial No. 562,077.

Each of the contact members 9 is provided with a foot portion 10 whichextends parallel to the face of the end of the cylinder 3 for contactwith the segments thereof.

The portions 19 of the contact members 9 may be slotted, as indicated at11, to compensate for any irregularities in the contact surface of thecylinder 3 that may exist by reason of slight differences in the lengthof the commutator segments and to insure an eflicient electrical contacttherewith. The contact members 9 are each provided with a plurality ofweights 12 which are riveted in apertures formed in the members 10, asat 13.

The contact members 9 are adjusted, with respect to the extremities ofthe commutator segments, by means of fingers 14 which are securedbetween the members 9 and the ring 5. The extremities of the fingers 14are provided with curled portions 15 that are adapt ed to be engaged bythe Contact members 9 and which provide seats or braces therefor. If itis desired to adjust the contact members 9, either toward or away fromthe ends of the commutator segments, the curled portions 15 of thefingers 14 may be bent outwardly or inwardly to correspondingly vary theposition of the seat.

During the starting period, the contact members 9 are out of contactwith the commutator segments and the machine therefore operates as arepulsion motor but, after the speed of the machine attains a.predetermined value, centrifugal force, acting on the weighted contactmembers, carries the same into engagement with the commutator segmentsand short circuits the windings of the rotor member which causes themachine to function as an induction motor during the normal operationthereof.

From the foregoing it will be apparent that, by means of the abovedescribed construction, a very inexpensive and efficientshort-circuiting device is provided that comprises but a few parts thatare easily manufactured and assembled.

I claim as my invention:

1. A short-circuiting device comprising a short-circuited member adaptedto be fixedly secured to the rotor member of a dynamo-electric machine,and a plurality of resilient contact members carried by saidshortcircuited member and having a free end projecting obliquely,inwardly toward the axis of the rotor member, said contact members beingarranged to swing outwardly under centrifugal action for engagement withthe commutator segments of said machine.

2. A short-circuiting device comprising a short-circ-uited memberadapted to be fixedly secured to the rotor member of a dynamo-electricmachine, and a plurality of weighted Contact members carried by saidshort-circuited member and having a free end projecting obliquely,inwardly toward the aXis of the rotor member, said contact members beingarranged to swing outwardly under centrifugal action for engagement withthe commutator segments of said machine.

3. A short-circuiting device comprising a supporting member adapted tobe fiXedly Secured to the rot-or member of a dynamoelectric machine, anda plurality of spring fingers, each spring finger having an end portionsecured to said supporting member, a free end portion projectingobliquely, inwardly toward the aXis of the rotor member and a weightattached at a point intermediate said end portions, said spring fingersbeing arranged to swing outwardly under centrifugal action forengagement with the commutator segments of said machine.

4. The combination with a coimnutatoi cylinder of a dynamo-electricmachine, of

a short-circuiting device comprising a circular supporting plate securedadjacent to said commutator cylinder in spaced relation to the end-faceof the saine, and a plurality of weighted spring fingers each having oneend secured to said supporting plate, the free ends of said springfingers projecting obliquely toward the inner portion of the end face ofsaid commutator cylinder and arranged to swing outwardly for making ashort-circuiting engagement with the end face of said commutatorcylinder.

5. The combination with a commutator cylinder of a dynamo-electricmachine, of a short-circuiting device comprising a circular supportingplate secured adjacent to said commutator cylinder in spaced relation tothe end-:tace of the same, a plurality of Weighted spring fingers eachhaving one end secured to said supporting plate, the free ends of saidspring ingers projecting obliquely toward the inner portion of the endface of said commutator cylinder and arranged to swing outwardly formaking ashort-circuiting engagement with the end face of said commutatorcylinder, said spring-fingers being biased to positions out of contactwith the commutator, and means for determining the extremeout-of-contact positions of said spring-fingers.

6i. The combination with a commutator cylinder of a dynamo-electricmachine, of a short-circuiting device comprising a circular supportingplate secured adjacent to said commutator cylinder, in spaced relationto the end-face of the same, and a plurality of weighted spring lingerseach having one end secured to said supporting plate, the free ends ofsaid spring fingers projecting obliquely toward the inner portion of theend face of said commutator cylinder and terminating in a contact-makingportion disposed substantially parallel to the endface of the commutatorcylinder, said spring-iingers being biased to positions outof-contactwith the commutator and arranged to swing outwardly under centrifugalaction whereby said parallel contactmaking portions come into engagementwith the face of said commutator.

7. The combination with a commutator cylinder of a dynamo-electricmachine, of a to the end-face of the same, a plurality of weightedspring fingers each having one end secured to said supporting plate, thefree ends of said spring fingers projecting obliquely toward the innerportion of the end face of said comniutator cylinder and terminating ina contact-making port-ion disposed substantially parallel to the endfaceot the commutator cylinder, said spring-fingers being biased topositions outof-contact with the commutator and arranged to swingoutwardly under'centrifugal action whereby said parallel contactmakingportions come into engagement with the face of said commutator, andmeans for determining the eXtreme out-of-contact positions of saidspring-fingers.

8. The combination with a commutator cylinder of a dynamo-electricmachine, of a short-circuiting device comprising a circular supportingplate secured adjacent to said commutator cylinder in spaced relation tothe end-face of the same, and a plurality of straps of resilientmaterial having end-portions secured to said supporting member andportions projecting obliquely toward the inner portion of saidcommutator cylinder, each obliquely projecting portion having at itsfree end a fiat contact making portion arranged to swing outwardly andmake a wiping contact with the face of said commutator.

9. The combination with a commutator cylinder of a dynamo-electricmachine, of a short-circuiting device comprising a circular supportingplate secured adjacent to said connnutator cylinder in spaced relationto the end-face of the same, and a plurality of sliort-circuitingweighted members having portions secured to said supporting member andportions projecting obliquely toward the inner portion of saidcommutator cylinder, each obliquely projecting portion having at itsfree end a flat Contact making portion arranged to swing outwardly tomake a wiping contact with the face of said commutator, said strapmembers being biased to positions out. of Contact with the commutator,and means comprising strap portions disposed underneath saidirst-mentioned strap portions and held b-y the same for determining theextreme out-of-oontaot positions to which said resilient straps arebiased.

In testimony whereof, I have hereunto subscribed my name this 28th dayof April HENRY D. MURDOCK.

